Carrier-Grade Ethernet Technology Based on the article: “Ethernet as a Carrier Grade Technology: Developments and Innovations” by R. Sanchez, L. Raptis, K. Vaxenavakis Raimena Veisllari TTM1 lecture 16.09.2011

Outline Repetition of the main Ethernet characteristics Reasons/Challenges for the Carrier Ethernet development Standardizations/work in progress Scalability through VLAN hierarchy Traffic Engineering (TE) Operation, Administration and Management (OAM) Deployment case study

The native Ethernet frame 7 octets Preamble for synchronization SFD (10101011) start of MAC frames 48 bit DA/SA CSMA/CD (do we still need it in switched Ethernet?) NOTE: When used to identify a hardware instance in new applications, the IEEE/RAC intends to migrate from MAC-48 to EUI-64 identifiers. However, for backward compatibility, this transition be difficult for some 802-related applications. Therefore, policies for allowing selective use of 48-bit identifiers within 802-related systems are being developed (see the following subclause for further details). MAC-48. A 48-bit identifier used to address hardware interfaces within existing 802 based networking applications EUI-48. A 48-bit identifier used to identify a design instance, as opposed to a hardware instance. Examples include software interface standards (such as VGA) or the model number for a product. EUI-64. A 64-bit identifier used to identify each hardware instance of a product, regardless of application, such as wireless devices and computerized toasters, as well as EUI-48 identifier applications.

Why did Ethernet “win” in the customer domain? There are LOTS of LAN protocols Price! Performance Availability Ease of use Scalability ….

Main characteristics Simplicity (plug n’play) and cost effective The switching logic (self-configuration) Listening, Learning and Forwarding Redundancy through xSTP VLAN known as a broadcast domain Connection-less (single hop)

Why Carrier Ethernet ? SP infrastrucure based on legacy circuit-switched SDH/SONET, ATM, frame relay etc. Ethernet as the technology of choice in the customer domain (85% of all networks and 95% of all LANs) Internet is packet-switched Eliminate potential internetworking problems High bandwidth with simplicity and low cost

Carrier Ethernet Definition The MEF1) has defined Carrier Ethernet as “an ubiquitous, standardized, carrier-class Service and Network defined by five attributes that distinguish Carrier Ethernet from familiar LAN based Ethernet” Standardized services Scalability Reliability QoS Service Management 1) http://metroethernetforum.org/index.php

Carrier Ethernet Challenges (1) Moving Ethernet from the LAN to the carrier network brings out requirements/challenges: Scalability Support for 10exp6 customers of an SP Evolving the VLAN-tagging standards Protection (Reliability and Resiliency) Achieve the required 50ms recovery time Problems with xSTP recovery time Other protocols required

Carrier Ethernet Challenges (2) 3. Quality of Service Hard QoS comparable with the guaranteed service from existing leased lines Service Management Service provisioning based to SLAs Service Monitoring Troubleshooting TDM support Inter-working with existing technologies (leverage the customer-driven investment)

Ethernet Standardization Milestones

Scalability through VLAN hierarchy(1) 802.1Q Management, security and scalability reasons 4094 available VLANs not enough for an SP Layer3 functions to communicate between VLANs

Scalability(2) Q-in-Q IEEE 802.1ad Provider Bridges adding a new S-VID to the frame, 4094 VLAN limitation for the provider! A failure in the customer’s domain still affects the spanning-tree of the provider’s core (transport) network http://en.wikipedia.org/wiki/IEEE_802.1ad

Scalability (3) MAC-in-MAC IEEE 802.1ah Provider Backbone Bridges (PBB) adds a Backbone MAC header

Scalability (4) - MAC-in-MAC header encapsulation - 24 bit I-SID ~16 service instances - Dedicated set of MAC addresses

Scalability through VLAN hierarchy(5) PBB provides: 1. 24 bit I-SID identifying the service in the SP => 16exp6 services 2. Total separation of the customer and SP networks The MAC header is added at the edge of the SP The backbone B-VID used for traffic engineering, ”zone”separation SP control frames are independent from the customer’s ones 3. Tunneling

PBB-Traffic Engineering PBB-TE 802.1Qay introduce connection-oriented forwarding mode and Ethernet tunnels: Deterministic service delivery, QoS Resiliency OAM requirements Turning off xSTP Forwarding is not based on the MAC learning mechanism but provided by the OAM plane

Ethernet Services MEF defines the services as Ethernet Virtual Connections (EVC): Point-to-point E-LINE Point-to-Multipoint E-Tree Multipoint-to-Multipoint E-LAN Private Leased Lines dedicated bandwidth Virtual Leased Lines shared bandwidth

Carrier network with PBT

Operation, Administration and Maintenance (OAM) Important building block toward carrier services Ethernet, multiple working/standardization bodies. IEEE 802.1ag and ITU-T Y.1731: Fault detection through Continuity Check Messages Fault verification through Loopback and reply messages Fault Isolation through Linktrace and reply messages

Operation, Administration and Maintenance (OAM) ITU-T Y.1731 Fault notification through Alarm Indication Signal Performance monitoring Frame Loss Ratio Frame Delay Frame Delay Variation

OAM example

Conclusions from the article Its simplicity and cost-effectiveness makes Ethernet a desirable technology for the NGN carrier networks Can Ethernet still be considered ”simple” after the discussed changes??? Native Ethernet is lacking capabilities for MAN and WAN environment.

Conclusions from the article PBB, PBB-TE and OAM aim to enhance Ethernet and provide the required carrier-grade services as from SONET/SDH, ATM and MPLS. The competing carrier technologies OTN and IP/MPLS will be discussed latter in the course schedule! Resiliency? Work in progress!

For further leisure reading Examples taken from “The road to Carrier-grade Ethernet” K. Fouli, M. Maier http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4804387 Metro Ethernet Forum MEF http://metroethernetforum.org/index.php